Model test on rock stress characteristics around gob-side entry in deep coalmine

Taking the deep gob-side entry excavation in Zhaolou coalmine as the engineering background, the stress characteristics around gob-side entry in deep coalmine was analyzed during the mining and roadway excavation in the last working face and the mining in current working face by adopting large-scale geomechanical model test system. The surrounding rock stress distribution characteristics corresponding to different coal pillar widths was studied. Finally, the corresponding engineering measures were put forward. Results show that: the stress peak values and distributions with different coal pillar widths vary during roadway excavation. The vertical stress distribution is approximately triangular when coal pillar width being 3-6 m, while that is trapezoidal for 8 m pillar width. Meanwhile, with the increase in coal pillar width, the maximum vertical stress rises. Coal entity peak stress with different coal pillar widths are greater than the that of coal pillar. With the increase in pillar width, coal entity is more close to the biggest abutment pressure position, which is not good to the roadway support. During mining, when the coal pillar width being less than 3 m, the peak stress of pillar increases first before decreasing with the increase in overload level. When the pillar width being greater than 5 m, the peak stress of coal pillar keeps increasing, but the growth rate decreases. The shallow coal pillar stress decreases gradually. The solid coal peak stress continues to increase, and the peak stress position gradually transfers to deep coal. Engineering practice shows that roadway deformation during mining are effectively controlled. Research results could provide references for determining reasonable coal pillar width and roadway support parameters and strength. © 2019, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.